Ilg W, Giese M A, Gizewski E R, Schoch B, Timmann D
Section Computational Sensomotorics, Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
Brain. 2008 Nov;131(Pt 11):2913-27. doi: 10.1093/brain/awn246. Epub 2008 Oct 3.
Cerebellar ataxic gait is influenced greatly by balance disorders, most likely caused by lesions of the medial zone of the cerebellum. The contributions of the intermediate and lateral zone to the control of limb dynamics for gait and the adaptation of locomotor patterns are less well understood. In this study, we analysed locomotion and goal-directed leg movements in 12 patients with chronic focal lesions after resection of benign cerebellar tumours. The extent of the cortical lesion and possible involvement of the cerebellar nuclei was determined by 3D-MR imaging. The subjects (age range 13-39 years, mean 20.3; seven female; ICARS score: mean 5.7, SD 6.3) performed three tasks: goal-directed leg placement, walking and walking with additional weights on the shanks. Based on the performance on the first two tasks, patients were categorized as impaired or unimpaired for leg placement and for dynamic balance control in gait. The subgroup with impaired leg placement but not the subgroup with impaired balance showed abnormalities in the adaptation of locomotion to additional loads. A detailed analysis revealed specific abnormalities in the temporal aspects of intra-limb coordination for leg placement and adaptive locomotion. These findings indicate that common neural substrates could be responsible for intra-limb coordination in both tasks. Lesion-based MRI subtraction analysis revealed that the interposed and the adjacent dentate nuclei were more frequently affected in patients with impaired compared to unimpaired leg placement, whereas the fastigial nuclei (and to a lesser degree the interposed nuclei) were more frequently affected in patients with impaired compared with unimpaired dynamic balance control. The intermediate zone appears thus to be of particular importance for multi-joint limb control in both goal-directed leg movements and in locomotion. For locomotion, our results indicate an influence of the intermediate zone on dynamic balance control as well as on the adaptation to changes in limb dynamics.
小脑性共济失调步态受平衡障碍的影响很大，很可能是由小脑内侧区病变引起的。对于小脑中间区和外侧区在控制步态的肢体动力学以及运动模式适应性方面的作用，人们了解得较少。在本研究中，我们分析了12例在切除良性小脑肿瘤后出现慢性局灶性病变的患者的运动和目标导向性腿部运动。通过三维磁共振成像确定皮质病变的范围以及小脑核团可能受累的情况。受试者（年龄范围13 - 39岁，平均20.3岁；7名女性；国际小脑共济失调评分量表（ICARS）评分：平均5.7，标准差6.3）进行了三项任务：目标导向性腿部放置、行走以及在小腿上额外负重行走。根据前两项任务的表现，将患者分为腿部放置受损或未受损以及步态动态平衡控制受损或未受损的亚组。腿部放置受损的亚组而非平衡受损的亚组在运动适应额外负荷方面表现出异常。详细分析揭示了腿部放置和适应性运动在肢体内部协调时间方面的特定异常。这些发现表明，在这两项任务中，共同的神经基质可能负责肢体内部协调。基于病变的磁共振成像减法分析显示，与腿部放置未受损的患者相比，腿部放置受损的患者中，间位核和相邻的齿状核更常受累，而与动态平衡控制未受损的患者相比，动态平衡控制受损的患者中，顶核（以及程度较轻的间位核）更常受累。因此，中间区在目标导向性腿部运动和行走中对多关节肢体控制似乎特别重要。对于行走，我们的结果表明中间区对动态平衡控制以及对肢体动力学变化的适应性有影响。
